Buggy code:
public class PatternCheckerVaadinDialog extends AbstractDialog < PatternCheckerConfig_V1 > { private GridLayout propertiesGridLayout ; private ComboBox regExp ; private TextArea detailsText ; public PatternCheckerVaadinDialog ( ) { } @ Override public void setConfiguration ( PatternCheckerConfig_V1 c ) throws DPUConfigException { } @ Override public PatternCheckerConfig_V1 getConfiguration ( ) throws DPUConfigException { } public String fieldValidation ( int column , int row ) { String txtValue ; String error = "" ; Component cmp = propertiesGridLayout . getComponent ( column , row ) ; if ( column == 0 ) { TextField txt = ( ( TextField ) ( cmp ) ) ; txtValue = txt . getValue ( ) . toLowerCase ( ) . trim ( ) ; if ( txtValue . isEmpty ( ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.subject.not.filled" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; txt . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.subject.not.filled" ) ) ) ; } else if ( ! ( txtValue . startsWith ( "http:////" ) ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.subject.not.http" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; txt . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.subject.not.http" ) ) ) ; } else if ( txtValue . contains ( "<seq2seq4repair_space>" ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.subject.whitespace" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; txt . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.subject.whitespace" ) ) ) ; } else { txt . setComponentError ( null ) ; } } else if ( column == 1 ) { TextField txt = ( ( TextField ) ( cmp ) ) ; txtValue = txt . getValue ( ) . toLowerCase ( ) . trim ( ) ; if ( txtValue . isEmpty ( ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.property.not.filled" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; txt . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.property.not.filled" ) ) ) ; } else if ( ! ( txtValue . startsWith ( "http:////" ) ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.property.not.http" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; txt . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.property.not.http" ) ) ) ; } else if ( txtValue . contains ( "<seq2seq4repair_space>" ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.property.whitespace" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; txt . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.property.whitespace" ) ) ) ; } else { txt . setComponentError ( null ) ; } } else { ComboBox combo = ( ( ComboBox ) ( cmp ) ) ; txtValue = ( ( String ) ( combo . getValue ( ) ) ) ; <START_BUG> ACC6Config_V1 c = new ACC6Config_V1 ( ) ; <END_BUG> Map < String , String > filters = c . getFilters ( ) ; if ( ( txtValue == null ) || ( txtValue . toLowerCase ( ) . trim ( ) . isEmpty ( ) ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.regex.not.filled" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; combo . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.regex.not.filled" ) ) ) ; } else if ( ( txtValue . toLowerCase ( ) . trim ( ) . contains ( "<seq2seq4repair_space>" ) ) && ( ! ( filters . containsKey ( txtValue ) ) ) ) { error = ( ( ( ( error + "\n" ) + ( ctx . tr ( "ACC6.error.regex.whitespace" ) ) ) + "<seq2seq4repair_space>[Row:<seq2seq4repair_space>" ) + row ) + "]" ; combo . setComponentError ( new com . vaadin . server . UserError ( ctx . tr ( "ACC6.error.regex.whitespace" ) ) ) ; } else { combo . setComponentError ( null ) ; } if ( ! ( error . isEmpty ( ) ) ) combo . removeItem ( txtValue ) ; } return error ; } public String fieldsValidation ( ) { } @ Override public void buildDialogLayout ( ) { } private void addColumnToPropertyMapping ( final String subject , final String property , final String regExp ) { } private void setRegexDetails ( String regex ) { } private void addColumnToPropertyMappingsHeading ( ) { } private void initComboBox ( ) { } No newline ; at end ; of file ; }

Fix:
PatternCheckerConfig_V1 c = new PatternCheckerConfig_V1 ( ) ;